1 Department of Medical Physics, Greater Poland Cancer Centre, University of Medical Sciences, Garbary 15, 61-866 Poznan, Poland ; Department of Electroradiology, University of Medical Sciences, Garbary 15, 61-866 Poznan, Poland.
2 Department of Medical Physics, Greater Poland Cancer Centre, University of Medical Sciences, Garbary 15, 61-866 Poznan, Poland.